This project is primarily one of the NIAID; however, CCMD/CC has performed bronchoscopy with bronchoalveolar lavage (BAL) in both patients with Wegener's Granulomatosis (WG) and normal volunteers provided by the NIAID. The purpose of this ongoing, prospective analysis is to determine what are the cellular and chemical abnormalities of lavage fluid in patients with WG in order to further clarify the potential etiology (ies) for the lung disease in this disorder. To date, 20 patients with WG and 10 normal volunteers have undergone bronchoscopy in our department. The BAL specimens from patients with WG had a marked neutrophilic response not seen in our controls and not known to occur in patients with other granulomatous lung diseases. BAL from patients with WG also contains anti-neutrophil cytoplasmic antibody which implies that macrophage presentation of processed antigen from neutrophil cytoplasmic contents may be abnormal and play an important role in pathogenesis. No infectious agent has been identified yet in his ongoing project. This study is important because it analyzes the pathogenesis of lung disease in patients with Wegener's granulomatosis. To date this project has resulted in two papers accepted for publication in the American Review of Respiratory Disease and in a third manuscript dealing with the incidence of Pneumocystis carinii pneumonia in patients with Wegener's Granulomatosis is submitted to the American Review of Respiratory Disease.